Pattern-forming process using photosensitive resin composition

ABSTRACT

There are disclosed a photosensitive resin composition which comprises
         (A) a polyamic acid having recurring units represented by the formula (I):       

     
       
         
         
             
             
         
       
         
         
           
              wherein R 1  represents 
           
         
       
    
                         
and R 2  represents a divalent organic group, and
         (B) an acryl compound having an amino group,   and also a photosensitive resin composition for an i-line stepper which further comprises a photoinitiator in addition to the photosensitive resin composition.

This application is a Continuation application of application Ser. No09/482,859, filed Jan. 14, 2000 which, now abandoned is a Divisionalapplication of application Ser. No. 09/136,610, filed Aug. 20, 1998, nowU.S. Pat. No. 6,194,126, issued Feb. 27, 2001, which is a Divisionalapplication of application Ser. No. 08/664,515, filed Jun. 17, 1996, nowU.S. Pat. No. 5,856,059 issued Jan. 5, 1999, which is a Continuationapplication of application Ser. No. 08/299,628, filed Sep. 2, 1994, nowabandoned, the contents of Ser. No. 08/299,628 being incorporated hereinby reference in their entirety.

BACKGROUND OF THE INVENTION

This invention relates to a photosensitive resin composition and aphotosensitive resin composition for an i-line stepper which contains aphotoinitiator.

In the semiconductor industries, inorganic materials have conventionallybeen used for interlaminar insulation. Recently, organic materialshaving an excellent heat-resistance such as a polyimide resin have beenput to use as materials for interlaminar insulation because ofproperties thereof.

A process for forming a pattern in a semiconductor integrated circuit orforming a pattern of a circuit on a print substrate comprises complexand various steps such as film formation of a resist material on asubstrate surface; exposure of required portion to light; removal ofunnecessary portion by etching or the like; and washing of the substratesurface. Therefore, development of heat-resistant photosensitivematerials have been desired, which enables the required portion of theresist material to be remained as such and used as insulating materialseven after the pattern is formed by exposure to light and development.

As such a material, heat-resistant photosensitive materials comprising,for example, a photosensitive polyimide or a cyclized polybutadiene as abase polymer have been proposed. The photosensitive polyimide hasparticularly attracted attentions since it has an excellentheat-resistance and impurities contained therein can easily be removed.

As such a photosensitive polyimide, for example, one which comprises apolyimide precursor and a bichromate has been proposed for the firsttime in Japanese Patent Publication No. 17374/1974. This photosensitivepolyimide has an advantage that it has a photosensitivity suitable forpractical uses and also has a high film-forming ability. However, italso has a disadvantage that it has a low preservability and a lowstability and that a chromium ion remains in the polyimide, andtherefore it has not been put to practical use.

As another example, a photosensitive polyimide precursor in which aphotosensitive group is introduced into a polyamic acid (polyimideprecursor) by an ester bond has been proposed in Japanese PatentPublication No. 30207/1980. This material has a disadvantage that afinally obtained product contains a chloride since a step forintroducing the photosensitive group comprises a dehydrochlorinationreaction.

In order to avoid these problems, for example, a process for mixing acompound which contains a photosensitive group with a polyimideprecursor is disclosed in Japanese Provisional Patent Publication No.109828/1979; and a process for affording photosensitivity to a polyimideprecursor by reacting a functional group in the polyimide precursor witha functional group of a photosensitive group-containing compound isdisclosed in Japanese Provisional Patent Publications No. 24343/1981 andNo. 100143/1985.

However, the photosensitive polyimide precursor employs an aromaticmonomer having an excellent heat-resistance and mechanical property as afundamental structure and has a low light-transmittance in theultraviolet region because the polyimide precursor itself absorbs theultraviolet light. Therefore, photochemical reactions at the exposedportion are not sufficiently caused which results in the low sensitivityor unclear patterns.

Recently, the higher and higher reduction has increasingly been requiredfor a rule for producing a semiconductor, accompanied by the higherintegration of semiconductors. Therefore, in addition to a conventionalcontact/proximity exposing machine using parallel rays, a 1:1 projectionexposing machine called as a mirror projection and a reduced projectionexposing machine called as a stepper have increasingly been used. Thestepper utilizes monochromatic light such as a high power oscillationline of ultra-high pressure mercury lamp, an excimer laser. As thestepper, a g-line stepper which employs a visible light (wavelength of435 nm) called as a g-line of ultra-high pressure mercury lamp hasconventionally been used in many cases. However, further reduction ofprocessing rule has been required. The process has already been carriedout around the lower limit of diffraction of light and therefore it isrequired to shorten the wavelength of the stepper used for carrying outfiner processing. Thus an i-line stepper having a wavelength of 365 nmhas increasingly been used instead of the g-line stepper having awavelength of 435 nm. However, a base polymer of a conventionalphotosensitive polyimide designed for the contact/proximity exposingmachine, the mirror projection exposing machine or the g-line stepper,having a low transparency for the above-described reason, hassubstantially no transmittance particularly for the i-line having awavelength of 365 nm. Therefore, the i-line stepper does not provide anyuseful pattern. On the other hand, as a polyimide film for surfaceprotection, a further thicker film has been required in-response to aLOC (lead on chip) which is a high density assembly method of asemiconductor element. When such a thicker film is used, the lowlight-transmittance causes more serious problem. For the above reasons,a photosensitive polyimide which is designed for the i-line stepper andhas a high transmittance for the i-line has been highly required.

SUMMARY OF THE INVENTION

The present invention is to overcome the above described problems and itis an object of the present invention to provide a photosensitive resincomposition and a photosensitive resin composition for an i-line stepperwhich contains a photoinitiator and-which transmits light to be used forexposure sufficiently and also has an excellent image-forming abilitywith an i-line stepper, film property, heat-resistance and adhesiveproperty.

The present invention relates to a photosensitive resin compositionwhich comprises (A) a polyamic acid having a recurring unit representedby the formula (I):

-   -   wherein R¹ represents

and R² represents a divalent organic group, and

(B) an acryl compound having an amino group, and relates to aphotosensitive resin composition for an i-line stepper which furthercomprises a photoinitiator in addition to the above photosensitive resincomposition.

DESCRIPTION OF THE PREFERRED EMBODIMENT

In the following, the present invention is explained in detail.

In the formula (I), R¹ is as defined above, and as R², there may bementioned a divalent aryl group such as

Of these, particularly preferred are

The polyamic acid (A) may contain at least one other recurring unit thanthe recurring unit represented by the formula (I). The recurring unitrepresented by the formula (I) is contained 20 to 100 mole % based onthe total amount of the recurring unit in the polyamic acid (A).

The polyamic acid (A) of the present invention can be obtained, forexample, by carrying out a ring-opening polyaddition reaction of an acidcomponent comprising oxydiphthalic acid or oxydiphthalic anhydride(trade name, 3,3′,4,4′-biphenyl ether tetracarboxylic dianhydride,hereinafter the same) and, if necessary, at least one othertetracarboxylic dianhydride, with a diamine in an organic solvent.

The oxydiphthalic acid and/or oxydiphthalic anhydride is/are used intotal in an amount of 20 to 100 mole % based on the total amount of theacid component.

As the other tetracarboxylic dianhydride which may be used if necessary,there may be mentioned, for example, an aromatic tetracarboxylicdianhydride such as pyrromellitic dianhydride,3,3′,4,4′-benzophenonetetracarboxylic dianhydride,3,3′,4,4′-biphenyltetracarboxylic dianhydride,1,2,5,6-naphthalenetetracarboxylic dianhydride,2,3,6,7-naphthalenetetracarboxylic dianhydride,2,3,5,6-pyridinetetracarboxylic dianhydride,1,4,5,8-naphthalenetetracarboxylic dianhydride,3,4,9,10-perylenetetracarboxylic dianhydride, sulfonyldiphthalicanhydride, m-terphenyl-3,3′,4,4′-tetracarboxylic dianhydride,p-terphenyl-3,3′,4,4′-tetracarboxylic dianhydride,1,1,1,3,3,3-hexafluoro-2,2-bis(2,3- or 3,4-dicarboxyphenyl) propanedianhydride, 2,2-bis(2,3- or 3,4-dicarboxyphenyl)propane dianhydride,2,2-bis{4-(2,3- or 3,4-dicarboxyphenoxy)phenyl}propane dianhydride,1,1,1,3,3,3-hexafluoro-2,2-bis{4-(2,3- or3,4-dicarboxyphenoxy)phenyl}propane dianhydride and a tetracarboxylicanhydride represented by the formula (II):

wherein R³ and R⁴ may be the same or different from each other and eachrepresent a monovalent hydrocarbon group; s is an integer of 1 to 5; andwhen s is 2 or more, respective R³s or R⁴s may be the same or differentfrom each other,and the above tetracarboxylic dianhydrides may be used singly or incombination of two or more.

In the formula (II), the monovalent hydrocarbon group of R³ and R⁴ mayinclude an alkyl group having 1 to 6 carbon atoms such as a methylgroup, an ethyl group, a n-propyl group, an isopropyl group, a n-butylgroup, an isobutyl group, a sec-butyl group, a tert-butyl group, apentyl group and a hexyl group; and a phenyl group, said phenyl groupmay be substituted by an alkyl group having 1 to 6 carbon atoms.

The above tetracarboxylic dianhydrides may be used if necessary inaddition to oxydiphthalic anhydride which is an essential component. Itmay be used in an amount of 80 mole % or less based on the total amountof the acid component so that the transmittance of the formed polyamicacid is not lowered.

As the above diamine, which are not particularly limited, there maypreferably be used 4,4′-diaminodiphenyl ether, 2,4′-diaminodiphenylether, 3,4′-diaminodiphenyl ether, 3,3′-diaminodiphenyl ether,4,4′-diaminodiphenyl sulfone, 3,3′-diaminodiphenyl sulfone andmetaphenylenediamine. Among them, 3,4′-diaminodiphenyl ether,3,3′-diaminodiphenyl sulfone, 4,4′-diaminodiphenyl sulfone andmethaphenylenediamine are more preferred. These compounds may be usedsingly or in combination of two or more.

In addition to the above diamine, there may be used with an amount whichdoes not lower the transmittance of the resulting polyimide precursor,for example, p-phenylenediamine, p-xylylenediamine,1,5-diaminonaphthalene, 3,3′-dimethylbenzidine, 3,3′-dimethoxybenzidine,4,4′- (or 3,4′-, 3,3′-, 2,4′-, 2,2′-) diaminodiphenylmethane,2,2′-diaminodiphenyl ether, 3,4′- (or 2,4′-, 2,2′-)diaminodiphenylsulfone, 4,4′- (or 3,4′-, 3,3′-, 2,4′-, 2,2′-)diaminodiphenylsulfide,4,4′-benzophenonediamine, bis{4-(4′-aminophenoxy)phenyl}sulfone,1,1,1,3,3,3-hexafluoro-2,2-bis(4-aminophenyl)propane,2,2-bis{4-(4′-aminophenoxy)phenyl}propane,3,3,-dimethyl-4,4′-diaminodiphenylmethane,3,3′,5,5′-tetramethyl-4,4′-diaminodiphenylmethane,bis{4-(3′-aminophenoxy)phenyl}sulfone, 2,2-bis(4-aminophenyl)propane,and an aliphatic diamine such as a diaminopolysiloxane represented bythe formula (III):

wherein R⁵ and R⁶ each represent a divalent hydrocarbon group,preferably a divalent hydrocarbon group having 1 to 3 carbon atoms; R⁷and R⁸ each represent a monovalent hydrocarbon group, preferably amonovalent hydrocarbon group having 1 to 3 carbon atoms; each of R⁵, R⁶,R⁷ and R⁸'s may be the same or different; and t represents an integer of1 to 5.

As the above diaminopolysiloxane, there may be used, for example,1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane.

An amount of the compound of the formula (III) may be 1 to 10 mole %based on the total amount of the diamine component.

There may be also used a hydroxyl group-containing diamine such as3,3′-hydroxybenzidine, 3,4′-diamino-3′,4-dihydroxybiphenyl,3,3,-dihydroxy-4,4′-diaminodiphenyloxide,3,3′-dihydroxy-4,4′-diaminodiphenylsulfone,2,2-bis(3-amino-4-hydroxyphenyl)propane,1,1,1,3,3,3-hexafluoro-2,2-bis-(3-amino-4-hydroxyphenyl)propane,bis-(3-hydroxy-4-aminophenyl)methane,3,3′-dihydroxy-4,4′-diaminobenzophenone,1,1-bis(3-hydroxy-4-aminophenyl)ethane,2,2-bis-(3-hydroxy-4-aminophenyl)propane,1,1,1,3,3,3-hexafluoro-2,2-bis-(3-hydroxy-4-aminophenyl)propane,1,3-diamino-4-hydroxybenzene, 1,3-diamino-5-hydroxybenzene,1,3-diamino-4,6-dihydroxybenzene, 1,4-diamino-2-hydroxybenzene, and1,4-diamino-2,5-dihydroxybenzene. These compounds may be used singly orin combination of two or more.

As the organic solvent to be used for the above reaction, a polarsolvent which completely dissolves the formed polyimide precursor isgenerally preferred. There may be mentioned, for example,N-methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide,dimethylsulfoxide, tetramethylurea, hexamethylphosphoric triamide andγ-butyrolactone.

In addition to these polar solvents, ketones, esters, lactones, ethers,halogenated hydrocarbons, hydrocarbons, for example, acetone, methylethyl ketone, methyl isobutyl ketone, cyclohexanone, methyl acetate,ethyl acetate, butyl acetate, diethyl oxalate, diethyl malonate, diethylether, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether,tetrahydrofurane, dichloromethane, 1,2-dichloroethane,1,4-dichlorobutane, trichloroethane, chlorobenzene, o-dichlorobenzene,hexane, heptane, octane, benzene, toluene, and xylene.

These organic solvents may be used singly or in combination of two ormore.

The organic solvent is used in an amount of 50 to 95% by weight based onthe total amount of the ring-opening polyaddition reaction solution, andthe polar solvent is used in an amount of 40 to 100% by weight based onthe total amount of the organic solvent. If necessary, water may becontained in the solvent used for the above reaction. When water iscontained, the solvent including the organic solvent and water is usedin amount of 50 to 95% by weight based on the total amount of the abovesolution, and the amount of water is 0.5 to 6% by weight based on thetotal weight of the solvent.

The polyamic acid can be prepared by reacting the above acid componentand the diamine, for example, in an amount of preferably 0.8 to 1.2 interms of the molar ratio of the acid/the diamine, more preferably about1.0, at a temperature of 0 to 100° C. at around normal pressure for 30minutes to 10 hours.

The resulting polyamic acid has a number average molecular weight (Mn)of 3,000 to 200,000, preferably 5,000 to 100,000, more preferably 7,000to 50,000. Also, the resulting polyamic acid solution has a viscosity of1 to 300 poise, preferably 30 to 200 poise, and a solid component of 5to 50% by weight, preferably 10 to 30% by weight.

As the acryl compound having an amino group to be used as Component (B)in the present invention, there may be mentioned, for example,N,N-dimethylaminoethyl methacrylate, N,N-diethylaminoethyl methacrylate,N,N-dimethylaminopropyl methacrylate, N,N-diethylaminopropylmethacrylate, N,N-dimethylaminoethyl acrylate, N,N-diethylaminoethylacrylate, N,N-dimethylaminopropyl acrylate, N,N-diethylaminopropylacrylate, N,N-dimethylaminoethylacrylamide, andN,N-diethylaminoethylacrylamide. These acryl compounds may be usedsingly or in combination of two or more.

The acryl compound having an amino group (B) may be used in an amount ofpreferably 1 to 200% by weight, more preferably 5 to 50% by weight,based on the amount of the polyamic acid containing the recurring unitrepresented by the formula (I) in consideration of photosensitivity andstrength of the heat-resistant film. When the acryl compound is used,affinity with the polyamic acid can be improved.

The photosensitive resin composition of the present invention maycontain, if necessary, (C) a photoinitiator as shown below. Such acomposition can be used as a photosensitive resin composition for ani-line stepper. As the photoinitiator (C), there may be mentioned, forexample, Michler's ketone, benzoin methyl ether, benzoin ethyl ether,benzoin isopropyl ether, 2-t-butylanthraquinone, 2-ethylanthraquinone,4,4′-bis(diethylamino)benzophenone, acetophenone, benzophenone,thioxanthone, 2,2-dimethoxy-2-phenylacetophenone, 1-hydroxycyclohexylphenyl ketone, 2-methyl-[4-(methylthio)phenyl]-2-morpholino-1-propanone,benzil, diphenyldisulfide, phenanthrenequinone, 2-isopropylthioxanthone,riboflavin tetrabutyrate,2,6-bis(p-diethylaminobenzal)-4-methyl-4-azacyclohexanone,N-ethyl-N-(p-chlorophenyl)glycine, N-ethyl-N-(p-chlorophenyl)glycine,N-phenyl-diethanolamine,2-(o-ethoxycarbonyl)oxyimino-1,3-diphenylpropanedione,1-phenyl-2-(o-ethoxycarbonyl)oxyiminopropan-1-one,3,3′,4,4′-tetra(t-butylperoxycarbonyl)benzophenone,3,3′-carbonylbis(7-diethylaminocoumarin),bis(cyclopentadienyl)-bis[2,6-difluoro-3-(pyri-1-yl)phenyl]titanium.These compounds may be used singly or in combination of two or more.

The photoinitiator (C) may be used in an amount of preferably 0.01 to30% by weight, more preferably 0.05 to 10% by weight based on thepolyamic acid (A) having the recurring unit represented by the formula(I) in consideration of photosensitivity and strength of the film.

The photosensitive resin composition may contain, if necessary, anaddition-polymerizable compound (D) as shown below. As theaddition-polymerizable compound (D), there may be mentioned, forexample, diethylene glycol diacrylate, triethylene glycol diacrylate,tetraethylene glycol diacrylate, diethylene glycol dimethacrylate,triethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate,trimethylolpropane diacrylate, trimethylolpropane triacrylate,trimethylolpropane dimethacrylate, trimethylolpropane trimethacrylate,1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, 1,4-butanedioldimethacrylate, 1,6-hexanediol methacrylate, pentaerythritoltriacrylate, pentaerythritol tetraacrylate, pentaerythritoltrimethacrylate, pentaerythritol tetramethacrylate, styrene,divinylbenzene, 4-vinyltoluene, 4-vinylpyridine, N-vinylpyrrolidone,2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate,1,3-acryloyloxy-2-hydroxypropane, 1,3-methacryloyloxy-2-hydroxypropane,methylenebis(acrylamide), N,N-dimethylacrylamide, andN-methylolacrylamide. These compounds may be used singly or incombination of two or more.

The addition-polymerizable compound (D) may preferably be used in anamount of 1 to 200% by weight based on the polyamic acid having therecurring unit represented by the formula (I) in consideration ofsolubility in a developer, photosensitivity or strength of the film.

The photosensitive resin composition of the present invention maycontain, if necessary, an azido compound (E) as shown below. As theazido compound (E), there may be mentioned, for example, the followingcompounds:

The azido compound may be used singly or in combination of two or more.

These compounds (E) may be used in an amount of preferably 0.01 to 30%by weight, more preferably 0.05 to 10% by weight based on the polyamicacid having the recurring unit represented by the formula (I) inconsideration of photosensitivity and strength of the film.

The photosensitive resin composition of the present invention maycontain a radical polymerization-inhibiting agent or a radicalpolymerization-suppressing agent such as p-methoxyphenol, hydroquinone,pyrogallol, phenothiazine, and a nitrosoamine.

The photosensitive resin composition of the present invention may beapplied to a substrate such as a silicon wafer, a metal substrate, aglass substrate and a ceramic substrate by a dipping method, a sprayingmethod, a screen printing method or a spinner coating method, thenheat-dried to evaporate most of the solvent so that a film having notackiness can be obtained.

The film is irradiated with active rays or chemical rays through a maskhaving required patterns. The material of the present invention issuitable for an i-line stepper, but a contact/proximity exposing machineemploying an ultrahigh-pressure mercury lamp, a mirror projectionexposing machine (aligner), a g-line stepper or the other sources ofultraviolet rays, far-ultraviolet rays, visible light, X rays orelectron rays may be used as the source of active rays or chemical raysfor irradiation. Among them, ultraviolet ray source may preferably beused as well as the i-line stepper. The required relief pattern can beobtained by dissolving and removing the non-irradiated portion with anappropriate developer after the irradiation.

As the developer, there may be used a good solvent having a highdissolving power such as N,N-dimethylformamide, N,N-dimethylacetamideand N-methyl-2-pyrrolidone, a mixed solvent of the above and a poorsolvent having a low dissolving power such as a lower alcohol, water andan aromatic hydrocarbon, or a basic solution such as tetramethylammoniumhydroxide aqueous solution and triethanolamine aqueous solution. Afterthe development, the film was rinsed with water or a poor solvent anddried at around 100° C. so that the pattern is stabilized. The reliefpattern is heated at 200 to 500° C., preferably 300 to 400° C. forseveral tens of minutes to several hours to form a highly heat-resistantpolyimide having patterns.

The photosensitive resin composition of the present invention can bethus converted to a buffer coating film of a semiconductor or aninterlaminar insulating film of a multi-layer wiring board.

EXAMPLES

The present invention is described in detail by referring to Examplesand Comparative examples, but the scope of the invention is not limitedby these Examples.

Synthetic Example 1

To a 100 ml-flask equipped with a stirrer, a thermometer and an inletfor introducing nitrogen gas were added 9.8917 g of 3,4′-diaminodiphenylether, 0.6462 g of 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane,2.2484 g of water, 14.60 g of xylene and 58.38 g ofN-methyl-2-pyrrolidone, and the mixture was dissolved by stirring undernitrogen flow at room temperature. Then, 16.4534 g of oxydiphthalicanhydride was added to the solution and the mixture was stirred for 5hours to have a tacky polyamic acid (polyimide precursor) solution. Thesolution was heated at 70° C. for adjusting the viscosity at 80 poise tohave a polymer solution called as P-1.

Synthetic Example 2

To a 500 ml flask equipped with a stirrer, a thermometer and an inletfor introducing nitrogen gas were added 49.4583 g of2,4′-diaminodiphenyl ether, 3.2308 g of1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane, 72.10 g of xyleneand 288.42 g of N-methyl-2-pyrrolidone and the mixture was dissolved bystirring at room temperature under nitrogen flow. Then, 80.6541 g ofoxydiphthalic anhydride was added and the mixture was stirred for 5hours to have a tacky polyamic acid (polyimide precursor) solution. Thesolution was then heated at 70° C. for adjusting the viscosity at 80poise to have a polymer solution called as P-2.

Synthetic Example 3

To a 500 ml flask equipped with a stirrer, a thermometer and an inletfor introducing nitrogen gas were added 57.0855 g of3,3′-diaminodiphenylsulfone, 3.0071 g of1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane, 73.09 g of xyleneand 292.35 g of N-methyl-2-pyrrolidone and the mixture was dissolved bystirring at room temperature under nitrogen flow. Then, 75.0703 g ofoxydiphthalic anhydride was added to the solution and the mixture wasstirred for 5 hours to have a tacky polyamic acid (polyimide precursor)solution. The solution was then heated at 70° C. for adjusting theviscosity at 80 poise to have a polymer solution called as P-3.

Synthetic Example 4

To a 500 ml flask equipped with a stirrer, a thermometer and an inletfor introducing nitrogen gas were added 57.0855 g of4,4′-diaminodiphenylsulfone, 3.0071 g of1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane, 73.09 g of xyleneand 292.35 g of N-methyl-2-pyrrolidone and the mixture was dissolved bystirring at room temperature under nitrogen flow. Then, 75.0703 g ofoxydiphthalic anhydride was added to the solution and the mixture wasstirred for 5 hours to have a tacky polyamic acid (polyimide precursor)solution. The solution-was heated at 70° C. for adjusting the viscosityat 80 poise to have a polymer solution called as P-4.

Synthetic Example 5

To a 100 ml-flask equipped with a stirrer, a thermometer and an inletfor introducing nitrogen gas were added 6.3697 g ofmethaphenylenediamine, 0.7704 g of1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane, 2.6808 g of water,14.47 g of xylene and 57.88 g of N-methyl-2-pyrrolidone and the mixturewas dissolved by at room temperature under nitrogen flow. Then, 19.6176g of oxydiphthalic anhydride was added to the solution and the mixturewas stirred for 5 hours to have a tacky polyamic acid (polyimideprecursor) solution. The solution was then heated at 70° C. foradjusting the viscosity at 80 poise to have a polymer solution called asP-5.

Synthetic Example 6

To a 200 ml-flask equipped with a stirrer, a thermometer and an inletfor introducing nitrogen gas were added 19.5931 g of4,4′-diaminodiphenyl ether, 1.2799 g of1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane, 4.4536 g of water,29.26 g of γ-butyrolactone and 117.02 g of N-methyl-2-pyrrolidone andthe mixture was dissolved by stirring at room temperature under nitrogenflow. Then, 33.2295 g of oxydiphthalic anhydride was added to thesolution and the mixture was stirred for 5 hours to have a polyamic acid(polyimide precursor) solution. The solution was then heated at 70° C.for adjusting the viscosity at 80 poise to have a polymer solutioncalled as P-6.

Synthetic Example 7

To a 100 ml-flask equipped with a stirrer, a thermometer and an inletfor introducing nitrogen gas were added 11.9841 g of4,4′-diaminodiphenyl ether, 0.7829 g of1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane, 2.7240 g of water,14.48 g of xylene and 57.93 g of N-methyl-2-pyrrolidone and-the mixturewas dissolved by stirring at room temperature under nitrogen flow. Then,14.0161 g of pyromellitic dianhydride was added to the solution and themixture was stirred for 5 hours to have a tacky polyamic acid (polyimideprecursor) solution. The solution was then heated at 70° C. foradjusting the viscosity at 80 poise to have a polymer solution called asP-7.

Synthetic Example 8

To a 100 ml-flask equipped with a stirrer, a thermometer and an inletfor introducing nitrogen gas were added 10.0819 g of4,4′-diaminodiphenyl ether, 0.6586 g of1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane, 2.2916 g of water,14.41 g of xylene and 90.05 g of N-methyl-2-pyrrolidone and the mixturewas dissolved by stirring at room temperature under nitrogen flow. Then,15.9049 g of biphenyltetracarboxylic dianhydride was added to thesolution and the mixture was stirred for 5 hours to have a polyamic acid(polyimide precursor) solution. The solution was then heated at 70° C.for adjusting the viscosity at 80 poise to have a polymer solutioncalled as P-8.

The transmittance at 365 nm of films of the polyamic acid (polyimideprecursor) solutions P-1 to P-8 prepared in Synthetic examples 1 to 8are shown in Table 1. The transmittance of the polyamic acid solutionwas determined by measuring the transmittance of a film obtained byspin-coating a glass substrate with the resin solution of the polyamicacid (polyimide precursor) and drying it at 85° C. for 3 minutes andthen at 105° C. for 3 minutes.

TABLE 1 Polyamic Transmittance (%) acid (thickness: 20 solution μm, at365 nm) Synthetic P-1 43 example 1 Synthetic P-2 48 example 2 SyntheticP-3 68 example 3 Synthetic P-4 60 example 4 Synthetic P-5 62 example 5Synthetic P-6 40 example 6 Synthetic P-7 less than 1 example 7 SyntheticP-8 less than 1 example 8

As can be seen from the above Table 1, the films obtained from thepolyamic acid solutions of the present invention (Synthetic examples 1to 6) had good transmittances to the light having a wavelength of 365 nm(i.e., i-line). To the contrary, in the films of comparative purpose(Synthetic examples 7 and 8), i-line light was substantially absorbed bythe films.

Examples 1 to 6

To each 10 g of the polyamic acid (polyimide precursor) solutions P-1 toP-6 prepared in Synthetic examples 1 to 6 were addedN,N-dimethylaminopropyl methacrylate (MDAP),2,6-bis(4′-azidobenzal)-4-carboxycyclohexanone (CA),4,4′-bis(diethylamino)benzophenone (EAB) and1-phenyl-2-(O-ethoxycarbonyl)oxyiminopropan-1-one (PDO) in a prescribedamount as shown in Table 2 and were mixed while stirring to have uniformphotosensitive resin composition solutions which were to be used inExamples 1 to 6, respectively.

Comparative Examples 1 and 2

To each 10 g of the polyamic acid (polyimide precursor) solutions P-7and P-8 prepared in Synthetic examples 7 to 8 were added MDAP, CA, EABand PDO in a prescribed amount as shown in Table 2 and were mixed whilestirring to have uniform photosensitive resin composition solutionswhich were to be used in Comparative examples 1 to 2, respectively.

TABLE 2 Polyamic acid Formulation (g) solution MDAP CA EAB PDO Example 1P-1 1.803 0.027 0.027 0.054 Example 2 P-2 1.803 0.027 0.027 0.054Example 3 P-3 1.656 0.027 0.027 0.054 Example 4 P-4 1.656 0.027 0.0270.054 Example 5 P-5 2.174 0.027 0.027 0.054 Example 6 P-6 1.803 0.0270.027 0.054 Comparative P-7 2.198 0.027 0.027 0.054 example 1Comparative P-8 1.861 0.027 0.027 0.054 example 2

MDAP, CA, EAB and PDO used in Examples 1 to 6 and Comparative examples 1to 2 were represented by the formulae:

MDAP (N,N-dimethylaminopropyl methacrylate):CH₂═C(CH₃) CO₂(CH₂)₃N(CH₃)₂;

CA (2,6-bis(4′-azidobenzal)-4-carboxycyclohexanone):

EAB (4,4′-bis(diethylamino)benzophenone):

PDO (1-phenyl-2-(O-ethoxycarbonyl)oxyiminopropan-1-one):

The each obtained solution was filtered and was drip spin-coated on asilicon wafer. Then, the wafer was heated at 100° C. for 150 seconds byusing a hot plate to form a film having a thickness of 20 μm and thefilm was exposed by using an i-line stepper through a mask havingpatterns. The film was heated at 110° C. for 50 seconds and subjected topuddle development using a mixed solution comprisingN-methyl-2-pyrrolidone and water with a weight ratio of 75:25. Then, thefilm was heated at 100° C. for 30 minutes, at 200° C. for 30 minutes andthen at 350° C. for 60 minutes under nitrogen atmosphere to have therelief pattern of the polyimide.

Evaluation results thereof are shown in Table 3. The resolution, thepost-developmental film-remaining ratio and the adhesive property wereevaluated using methods as mentioned below, respectively.

The resolution was evaluated as the minimal size of developablethrough-hole by using a through-hole test pattern.

The post-developmental film remaining ratio was determined as (thethickness after development/the thickness before development)×100 (%) bymeasuring the thicknesses of the film before and after the development.The film thickness was measured with a film thickness measurementapparatus, Dektak-3030 (trade name) manufactured by Sloan Co.

Adhesive property was measured as follows. A film (film thickness: 5 μm)obtained by coating a silicon wafer with the photosensitive resincomposition and heating it at 100° C. for 30 minutes, at 200° C. for 30minutes and then at 350° C. for 60 minutes was subjected to a PressureCooker test (conditions: at 121° C., 2 atmospheric pressure for 100hours) and then carried out a checkerboard test.

In the checkerboard test, the film was cut like a checkerboard by aknife so that 100 squares per 1 mm² are formed and peeled off by using acellophane tape regulated by Japanese Industrial Standard (JIS K5400) todetermine the ratio of the number of remaining squares to 100. Theresults are shown in Table 3.

TABLE 3 Post- development film- Resolution remaining Adhesive (μm)Pattern ratio (%) property Example 1 10 Good 95 100/100 Example 2 10Good 97 100/100 Example 3 10 Good 94 100/100 Example 4 10 Good 96100/100 Example 5 10 Good 96 100/100 Example 6 10 Good 98 100/100Comparative 60 Poor 65 100/100 Example 1 Comparative 60 Poor 58 100/100Example 2

The smaller the value of the resolution is, the finer the pattern can beobtained, therefore, the higher the integration of LSI can be obtained.The photosensitive resin composition of the present invention has aremarkably excellent resolution.

Generally speaking, while the photosensitive resin composition havingthe post-developmental film-remaining ratio of 90% or more is good forpractical use, the photosensitive resin composition having that of 60's% or less isn't suitable for practical use. Therefore, thephotosensitive resin composition of the present invention has aremarkably excellent post-developmental film-remaining ratio.

The photosensitive resin composition and the photosensitive resincomposition for an i-line stepper of the present invention which use apolyamic acid having excellent light-transmittance are excellent inimage-forming ability and particularly suitable for pattern-formationwith an i-line. The polyimide obtained therefrom is also excellent inmechanical properties, heat-resistance and adhesive property of thefilm.

1. A photosensitive resin composition which comprises (1) a polyimideprecursor produced using an oxydiphthalic acid or acid anhydride thereofand at least one diamine as reactants for forming the polyimideprecursor, wherein said at least one diamine consists of at least onediamine selected from the group consisting of diaminodiphenyl ether,diaminodiphenyl sulfone, metaphenylene diamine, p-phenylenediamine,p-xylylenediamine, diaminonaphthalene, dimethylbenzidine,dimethoxylbenzidine, diaminodiphenylmethane, diaminodiphenylsulfide,benzophenonediamine, bis{(aminophenoxy)phenyl}sulfone,hexafluoro-bis(aminophenyl)propane, bis{(aminophenoxy)phenyl}propane,dimethyl-diaminophenyl-methane, tetramethyl-diaminodiphenylmethane,bis{(aminophenoxy)phenyl}sulfone, bis(aminophenyl)propane anddiaminopolysiloxane, (2) an addition-polymerizable compound, and (3) aphotoinitiator, and which is adapted to be exposed and developed usingan i-line stepper which uses monochromatic light, the polyimideprecursor being such that a 20 μm thick firm thereof has atransmittance, at 365 nm, of at least 40%.
 2. A photosensitive resincomposition according to claim 1, wherein the addition-polymerizablecompound is tetraethylene glycol dimethacrylate.
 3. A photosensitiveresin composition according to claim 2, wherein said at least onediamine used in producing said polyimide precursor consists of adiaminopolysiloxane.
 4. A photosensitive resin composition according toclaim 2, wherein said transmittance is in a range of 40%–68%.
 5. Aphotosensitive resin composition according to claim 2, wherein said atleast one diamine used in producing said polyimide precursor consists ofa diaminodiphenyl ether.
 6. A photosensitive resin composition accordingto claim 1, wherein said at least one diamine used in producing saidpolyimide precursor consists of a diaminodiphenyl ether.
 7. Aphotosensitive resin according to claim 6, wherein said at least onediamine used in producing said polyimide precursor consists of at leastone diamine selected from the group consisting of 4,4′-diaminodiphenylether, 2,4′-diaminodiphenyl ether, 3,4′-diaminodiphenyl ether and3,3′-diamino-diphenyl ether.
 8. A photosensitive resin compositionaccording to claim 1, wherein said at least one diamine used inproducing said polyimide precursor consists of at least one diamineselected from the group consisting of 4,4′-diaminodiphenyl ether,2,4′-diaminodiphenyl ether, 3,4′-diaminodyphenyl ether,3,3′-diaminodiphenyl ether, 4,4′-diaminodiphenyl sulfone,3,3′-diaminodiphenyl sulfone and metaphenylenediamine.
 9. Aphotosensitive resin composition according to claim 8, wherein said atleast one diamine used in producing said polyimide precursor consists ofat least one diamine selected from the group consisting of3,4′-diaminodiphenyl ether, 3,3′-diaminodiphenyl sulfone,4,4′-diaminodiphenyl sulfone and metaphenylenediamine.
 10. Aphotosensitive resin composition according to claim 8, which consistsessentially of said polyimide precursor, said addition-polymerizablecompound, and said photoinitiator, in an organic solvent.
 11. Aphotosensitive resin composition according to claim 8, wherein saidpolyimide precursor, said addition-polymerizable compound and saidphotoinitiator are provided in an organic solvent.
 12. A photosensitiveresin composition according to claim 11, wherein composition is asolution of said polyimide precursor, said addition-polymerizablecompound and said photoinitiator in said organic solvent.
 13. Aphotosensitive resin composition according to claim 1, wherein the atleast one diamine used in producing said polyimide precursor, consistingof said at least one diamine selected from said group, includes adiaminopolysiloxane represented by the formula (III):

wherein R⁵ and R⁶ each represent a divalent hydrocarbon group; R⁷ R⁸each represent a monovalent hydrocarbon group; each of R⁵, R⁶, R⁷and R⁸may be the same or different; and t represents an integer of 1 to
 5. 14.A photosensitive resin composition according to claim 13, wherein saiddivalent hydrocarbon group has 1 to 3 carbon atoms, and said monovalenthydrocarbon group has 1 to 3 carbon atoms.
 15. A photosensitive resincomposition which comprises (1) a polyimide precursor produced using (a)an oxydiphthalic acid or acid anhydride thereof as a reactant forforming the polyimide precursor, and (b) at least one diamine includinga hydroxyl group-containing diamine, (2) an addition-polymerizablecompound, and (3) a photoinitiator, and which is adapted to be exposedand developed using an i-line stepper which uses monochromatic light,the polyimide precursor being such that a 20 μm thick film thereof has atransmittance, at 365 nm, of at least 40%.
 16. A photosensitive resincomposition according to claim 1, wherein said polyimide precursor is acondensation product of said oxydiphthalic acid or acid anhydridethereof and said at least one diamine.
 17. A photosensitive resincomposition which consists essentially of (1) a polyimide precursorproduced using (a) an oxydiphthalic acid or acid anhydride thereof as areactant for forming the polyimide precursor, and (b) at least onediamine selected from the group consisting of diaminodiphenyl sulfone,metaphenylene diamine, p-phenylenediamine, p-xylylenediamine,diaminonaphthalene, dimethylbenzidine, dimethoxylbenzidine,diaminodiphenylmethane, diaminodiphenylsulfide, benzophenonediamine,bis{(aminophenoxy)phenyl}sulfone, hexafluoro-bis(aminophenyl)propane,bis{(aminophenoxy)phenyl}propane, dimethyl-diaminophenyl-methane,tetramethyl-diaminodiphenylmethane, bis{(aminophenoxy)phenyl}sulfone,bis(aminophenyl)propane and diaminopolysiloxane, (2) anaddition-polymerizable compound, and (3) a photoinitiator, and which isadapted to be exposed and developed using an i-line stepper which usesmonochromatic light, the polyimide precursor being such that a 20 μmthick film thereof has a transmittance, at 365 nm, of at least 40%. 18.A photosensitive resin composition according to claim 1, which consistsessentially of said polyimide precursor, said addition-polymerizablecompound, and said photoinitiator, in an organic solvent.
 19. Aphotosensitive resin composition according to claim 15, wherein saidpolyimide precursor, said addition-polymerizable compound and saidphotoinitiator are in a solvent.
 20. A photosensitive resin compositionaccording to claim 17, wherein said polyimide precursor, saidaddition-polymerizable compound and said photoinitiator are in asolvent.
 21. A photosensitive resin composition according to claim 1,wherein said polyimide precursor is produced by using said oxydiphthalicacid or acid anhydride thereof and said at least one diamine asreactants, in an organic solvent.
 22. A photosensitive resin compositionaccording to claim 21, wherein said organic solvent is selected from thegroup consisting of N-methyl-2-pyrrolidone, N,N-dimethylacetamide,N,N-dimethylformamide, dimethylsulfoxide, tetramethylurea,hexamethylphosphoric triamide and γ-butyrolactone.
 23. A photosensitiveresin composition according to claim 1, wherein said polyimide precursorhas a number average molecular weight of 3,000 to 200,000.
 24. Aphotosensitive resin composition according to claim 23, wherein saidnumber average molecular weight of said polyimide precursor is 7,000 to50,000.
 25. A photosensitive resin composition according to claim 1,wherein said polyimide precursor, said addition-polymerizable compoundand said photoinitiator are provided in an organic solvent.
 26. Aphotosensitive resin composition according to claim 1, whereincomposition is a solution of said polyimide precursor, saidaddition-polymerizable compound and said photoinitiator in said organicsolvent.
 27. A photosensitive resin composition according to claim 1,wherein said polyimide precursor is produced using said oxydiphthalicacid.
 28. A photosensitive resin composition according to claim 17,wherein said polyimide precursor is produced using said oxydiphthalicacid.
 29. A photosensitive resin composition according to claim 1,wherein said photoinitiator is selected from the group consisting ofMichler's ketone, benzoin methyl ether, benzoin ethyl ether, benzoinisopropyl ether, 2-t-butylanthraquinone, 2-ethylanthraquinone,4,4′-bis(diethylamino)benzophenone, acetophenone, benzophenone,thioxanthone, 2,2-dimethoxy-2-phenylacetophenone, 1-hydroxycyclohexylphenyl ketono, 2-methyl-[4-(methylthio)phenyl]-2-morpholino-1-propanone,benzil, diphenyldisulfide, phenanthrenequinone, 2-isopropylthioxanthone,riboflavin tetrabutyrate,2,6-bis(p-diethylaminobenzal)-4-methyl-4-azacyclohexanone,N-ethyl-N-(p-chlorophenyl)glycine, N-phenyl-diethanolamine,2-(o-ethoxycarbonyl)oxyimino-1,3-diphenylpropanedione,1-phenyl-2-(o-ethoxycarbonyl)oxyiminopropan-1-one,3,3′,4,4′-tetra(t-butylperoxycarbonyl)benzophenone, and3,3′-carbonylbis(7-diethylaminocoumarin).
 30. A photosensitive resincomposition according to claim 17, wherein said photoinitiator isselected from the group consisting of Michler's ketone, benzoin methylether, benzoin ethyl ether, benzoin isopropyl ether,2-t-butylanthraquinone, 2-ethylanthraquinone,4,4′-bis(diethylamino)benzophenone, acetophenone, benzophenone,thioxanthone, 2,2-dimethoxy-2-phenylacetophenone, 1-hydroxycyclohexylphenyl ketone, 2-methyl-[4-(methylthio)phenyl]-2-morpholino-1-propanone,benzil, diphenyldisulfide, phenanthrenequinone, 2-isopropylthioxanthone,riboflavin tetrabutyrate,2,6-bis(p-diethylaminobenzal)-4-methyl-4-azacyclohexanone,N-ethyl-N-(p-chlorophenyl)glycine, N-phenyl-diethanolamine,2-(o-ethoxycarbonyl)oxyimino-1,3-diphenylpropanedione,1-phenyl-2-(o-ethoxycarbonyl)oxyiminopropan-1-one,3,3′,4,4′-tetra(t-butylperoxycarbonyl)benzophenone, and3,3′-carbonylbis(7-diethylaminocoumarin).
 31. A photosensitive resincomposition according to claim 1, wherein the oxydiphthalic acid or acidanhydride thereof is included in total in an amount of 20 to 100 mole %based on total amount of acid component of the polyimide precursor. 32.A photosensitive resin composition according to claim 17, wherein theoxydiphthalic acid or acid anhydride thereof is included in total in anamount of 20 to 100 mole % based on total amount of acid component ofthe polyimide precursor.